Device for monitoring blood flow

ABSTRACT

A medical device for measuring blood flow through a blood vessel of a mammal includes a conductive elastomer having a variable resistance. A frame is at least partially surrounding at least a portion of the conductive elastomer, the conductive elastomer is suspended within the frame. A mechanical amplification element is slidably engaged to the conductive elastomer, the mechanical amplification element being configured to slide within the frame and to contact skin of the mammal over the blood vessel when the frame is positioned over the blood vessel, the mechanical amplification element being configured to be displaced when the artery pulsates and changes the resistance of the elastomer.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation U.S. application Ser. No. 16/992,223filed Aug. 13, 2020, which is a Continuation-in-Part of and claimspriority to U.S. application Ser. No. 16/471,823, filed Jun. 20, 2019,and International Application No. PCT/EP2017/079918 filed on Nov. 21,2017, titled EQUIPMENT FOR MONITORING BLOOD FLOW AND RESPIRATORY FLOW,which is related to and claims priority to Belgian Patent ApplicationNo. 2016/5953 filed on Dec. 21, 2016, the entirety of which isincorporated by reference herein.

FIELD

The present technology is generally related to devices for measuring andmonitoring blood flow through a blood vessel.

BACKGROUND

Cardiac catherization is a minimally invasive procedure used to diagnoseor treat cardiac conditions. For example, percutaneous coronaryinterventions (PCI) are used to treat blockages in the heart with, forexample, balloon angioplasty, to improve blood flow. The catheter is fedthrough a larger artery for example, the femoral artery, and advancedtoward the vascular or cardiac site of interest for treatment. Owing tothe distance travelled and the risk of bleeding, physicians often usethe radial artery as the access point for PCI as opposed to the femoralartery. However, as with any surgical procedure, there is risk of damageto the blood vessel such as arterial occlusion.

SUMMARY

The techniques of this disclosure generally relate to devices formeasuring and monitoring blood flow through a blood vessel.

In one aspect, a medical device for measuring blood flow through a bloodvessel of a mammal includes a conductive elastomer having a variableresistance. A frame is at least partially surrounding at least a portionof the conductive elastomer, the conductive elastomer is suspendedwithin the frame. A mechanical amplification element is slidably engagedto the conductive elastomer, the mechanical amplification element beingconfigured to slide within the frame and to contact skin of the mammalover the blood vessel when the frame is positioned over the bloodvessel, the mechanical amplification element being configured to bedisplaced when the blood vessel pulsates and changes the resistance ofthe conductive elastomer.

In another aspect of this embodiment, the mechanical amplificationelement slides a predetermined distance within the frame.

In another aspect of this embodiment, the mechanical amplificationelement defines an atraumatic skin contact surface.

In another aspect of this embodiment, the mechanical amplificationelement defines an aperture opposite the atraumatic skin contactsurface, and wherein the conductive elastomer is slidably receivedwithin the aperture.

In another aspect of this embodiment, wherein the frame is configured toflex around a portion of at least one from the group consisting of a armand an leg of the mammal.

In another aspect of this embodiment, the mechanical amplificationelement is slidable within the frame from a first position in which thesensor does not measure blood flow through the blood vessel to a secondposition in the sensor measures blood flow through the blood vessel.

In another aspect of this embodiment, the device further includes anadhesive patch coupled to the frame and adherable to skin of the mammal.

In another aspect of this embodiment, the device further includes acontroller in communication with and coupled to the sensor.

In another aspect of this embodiment, the device further includesconductive electrical pathways disposed between the patch and frame.

In another aspect of this embodiment, the mechanical amplificationelement includes a gripping element extending outward therefrom.

In one aspect, a medical device for measuring blood flow through a bloodvessel of a mammal includes a conductive elastomer having a variableresistance. A frame substantially surrounds at least a portion of theconductive elastomer, the frame includes a first at least substantiallyclosed loop portion adjacent a second at least substantially closed loopportion. A first mechanical amplification element is slidably coupled tothe conductive elastomer and is disposed within the first at leastsubstantially closed loop portion. A second mechanical amplificationelement is slidably engaged to the conductive elastomer and disposedwithin the second at least substantially closed loop portion. The firstand second mechanical amplification element are configured to slidewithin their respective one of the first at least substantially closedloop portion and the second at least substantially closed loop portionand to contact skin of the mammal over the respective blood vessel whenthe frame is positioned over the respective blood vessel, the first andsecond mechanical amplification elements being to be displaced when therespective blood vessel pulsates and changes the resistance of theconductive elastomer

In another aspect of this embodiment, each of the first and secondmechanical amplification elements defines an atraumatic skin contactsurface.

In another aspect of this embodiment, each of the first and secondmechanical amplification elements defines an aperture opposite theatraumatic skin contact surface, and wherein the conductive elastomer isslidably received within the aperture.

In another aspect of this embodiment, the frame is configured to flexaround a portion of at least one from the group consisting of a wristand an ankle of the mammal.

In another aspect of this embodiment, the frame is composed of aflexible plastic.

In another aspect of this embodiment, the device further includes andadhesive patch coupled to the frame and adherable to skin of the mammal.

In another aspect of this embodiment, the device further includes acontroller in communication with and coupled to the conductiveelastomer.

In another aspect of this embodiment, the device further includesconductive electrical pathways disposed between the patch and frame.

In another aspect of this embodiment, wherein each of the first andsecond mechanical amplification elements includes a gripping elementextending outward therefrom.

In one aspect, a medical device for measuring blood flow through a bloodvessel of a mammal includes a conductive elastomer having a variableresistance. A frame surrounds at least a portion of the conductiveelastomer, the frame includes a first at least substantially closed loopportion adjacent a second at least substantially closed loop portion. Afirst mechanical amplification element is slidably coupled to theconductive elastomer and disposed within the first at leastsubstantially closed loop portion. A second mechanical amplificationelement is slidably coupled to the conductive elastomer and disposedwithin the second at least substantially closed loop portion. The firstand second mechanical amplification element are configured to slidewithin their respective one of the first at least substantially closedloop portion and the second at least substantially closed loop portionand to contact skin of the mammal over the respective blood vessel whenthe frame is positioned over the respective blood vessel, the first andsecond mechanical amplification elements are configured to be displacedwhen the respective blood vessel pulsates and changes the resistance ofthe conductive elastomer. An adhesive patch is coupled to the frame andadherable to the skin of the mammal, the adhesive patching defines atleast a substantially closed loop about the wrist of the mammal. Aprinted circuit board (PCB) is disposed between the patch and the frame.A controller is coupled to the sensor and the PCB and configured to bedisposed on at least a portion of wrist of the mammal, the controllerincludes a display configured to display blood flow measurements throughthe blood vessel

The details of one or more aspects of the disclosure are set forth inthe accompanying drawings and the description below. Other features,objects, and advantages of the techniques described in this disclosurewill be apparent from the description and drawings, and from the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete understanding of the present invention, and theattendant advantages and features thereof, will be more readilyunderstood by reference to the following detailed description whenconsidered in conjunction with the accompanying drawings wherein:

FIG. 1 is a disassembled view of a device for measuring and monitoringblood flow through a blood vessel.

FIG. 2A is a side view of the assembled device shown in FIG. 1;

FIG. 2B is a zoomed in view of the device shown in FIG. 2A;

FIG. 3 is a perspective view of the mechanical amplification elementshow in FIG. 1;

FIG. 4 is a top view of the printed circuit board shown in FIG. 1;

FIG. 5 is a perspective view of the assembled device shown in FIG. 1with a controller on the surface of the wrist;

FIG. 6 is perspective view of the device shown in FIG. 5 showing thecontroller coupled to the sensor; and

FIG. 7 is a cross-sectional view showing the mechanical amplificationelement shown in FIG. 3 being displaced by a pulsating blood vessel.

DETAILED DESCRIPTION

It should be understood that various aspects disclosed herein may becombined in different combinations than the combinations specificallypresented in the description and accompanying drawings. It should alsobe understood that, depending on the example, certain acts or events ofany of the processes or methods described herein may be performed in adifferent sequence, may be added, merged, or left out altogether (e.g.,all described acts or events may not be necessary to carry out thetechniques). In addition, while certain aspects of this disclosure aredescribed as being performed by a single module or unit for purposes ofclarity, it should be understood that the techniques of this disclosuremay be performed by a combination of units or modules associated with,for example, a medical device.

In one or more examples, the described techniques may be implemented inhardware, software, firmware, or any combination thereof. If implementedin software, the functions may be stored as one or more instructions orcode on a computer-readable medium and executed by a hardware-basedprocessing unit. Computer-readable media may include non-transitorycomputer-readable media, which corresponds to a tangible medium such asdata storage media (e.g., RAM, ROM, EEPROM, flash memory, or any othermedium that can be used to store desired program code in the form ofinstructions or data structures and that can be accessed by a computer).

Instructions may be executed by one or more processors, such as one ormore digital signal processors (DSPs), general purpose microprocessors,application specific integrated circuits (ASICs), field programmablelogic arrays (FPGAs), or other equivalent integrated or discrete logiccircuitry. Accordingly, the term “processor” as used herein may refer toany of the foregoing structure or any other physical structure suitablefor implementation of the described techniques. Also, the techniquescould be fully implemented in one or more circuits or logic elements.

Referring now to the drawings in which like reference designators referto like elements, there is shown in FIGS. 1-2A-2B an exemplary devicefor measuring and monitoring blood flow through a blood vessel anddesignated generally herein as “10.” In the configuration shown in FIG.1 the device is sized and configured to be at least partially wrappedaround a mammal's wrist, for example, a human or animal. In otherconfigurations, the device may be sized and configured to be positionedover the skin over any blood vessel, whether artery or vein within thebody of the mammal. The device 10 includes a frame 12 sized andconfigured to contour the skin of the mammal. The frame 12 may be rigidor flexible, and in one configuration is composed of a flexible plastic.The frame 12 may define at least one substantially closed loop. Forexample, as shown in FIGS. 1 and 2 the frame includes a firstsubstantially closed loop portion 14 adjacent to a second substantiallyclosed loop portion 16. Although shown as two loops, it is contemplatedthat the frame 12 may include any number of loops.

Extending through the frame 12 is a sensor 18 configured to measure asignal indicative of blood flow through a blood vessel. In particular,the sensor 18 is a conductive elastomer having a variable resistance.That is, the resistance of the sensor 18 changes as it is stretched,which can be measured and correlated into a flow measurement, asdiscussed in more detail in co-pending U.S. Patent Publication No.2020/0093378 the entirety of which is expressly incorporated byreference herein. In the configuration shown in FIGS. 1 and 2A-2B, thesensor 18 extends through a center of the frame 12 into both the firstsubstantially closed loop portion 14 and the second substantially closedloop portion 16. Disposed along and in communication with the sensor 18are one or more mechanical amplification elements 20. The mechanicalamplification elements 20 are configured to slide along the sensor 18within the frame 12, and therefore a predetermined distance based on thesize of the respective substantially closed loop portion 14, 16 and tocontact skin of the mammal over the blood vessel when the frame 12 ispositioned over the blood vessel. In particular, the mechanicalamplification elements 20, which may be composed of any rigidnon-conductive material, for example, plastic, wood, polymer, stone,etc., transfer vibrational energy from the pulsating blood vessel to thesensor 18. The vibrational energy stretches the sensor 18 which changesthe resistance of the sensor 18 which can be measured and correlatedinto a measure of flow. For example, an occluded artery, whether theulnar or radial artery, has little to no flow and thus transfer lessvibrational energy to the mechanical amplification elements 20 and thusto the sensor 18. Whereas a non-occluded artery has a higher flow andpulsates, which causes the displacement of the mechanical amplificationelements 20 and changes the resistance of the sensor 18 (as shown inFIG. 7). For example, as shown in FIG. 7, when the blood vessel isrelaxed, the blood vessel radius “R_(1A)” is and the mechanicalamplification element 20 is at a distance “x” between the skin surface21 and the blood vessel. As the blood vessel pulsates with blood flowduring systole, the radius of the blood vessel increases from “R_(1A)”to “R₂” and the distance between the mechanical amplification element 20and the blood vessel increases from distance “x” to “x′,” whichstretches the sensor 18. As the blood vessel relaxes during diastole,the radius of the blood vessel changes from “R₂” to R_(1B)″, thedistance between the mechanical amplification element 20 and the bloodvessel decreases from “x′” back to “x,” which relaxes the sensor 18.

In an exemplary configuration, a single mechanical amplification element20 a is included in the first substantially closed loop portion 14 offrame 12 and a single mechanical amplification element 20 b is includedint the second substantially closed loop portion 16 of frame 12. Themechanical amplification elements 20 may be slid over the sensor 18 to aposition over the blood vessel to be measured. For example, themechanical amplification element 20 a may be positioned over the radialartery and the mechanical amplification element 20 b may be positionedover the ulnar artery. The spacing between mechanical amplificationelements 20 may be between 5-80 mm such that the frame 12 canaccommodate any size wrist or spacing between the ulnar and radialarteries. In other configurations, mechanical amplification elements 20may be positioned over veins in the wrist of other areas of themammalian body.

Referring now to FIG. 3, the mechanical amplification elements 20include an atraumatic skin contact surface 22 opposite a grippingelement 24 which depends an aperture 26 therethrough. The atraumaticskin contact surface 22, which may hemispherical in shape or anyatraumatic shape is configured to contact the skin over the bloodvessel. In one configuration, the atraumatic skin contact surface 22also includes a thin adhesive layer such that it sticks to the skin whenpositioned over the skin until moved to a different position with thegripping element 24. In an exemplary configuration, the sensor 18 isdisposed within the aperture 26 such that the mechanical amplificationelement 20 slides along the sensor 18. Owing to the elevation of theaperture 26 at the top of the mechanical amplification element 20, thesensor 18 is pre-stretched within the mechanical amplification element20, as shown in FIG. 2B. In some configurations, each substantiallyclosed loop portion 14 and 16 defines an area with a wider diameter thanthe rest of the respective substantially closed loop portion 14 and 16.For example, the first substantially closed loop portion 14 may define awell 28 a sized and configured to receive the mechanical amplificationelement 20 a and similarly, the second substantially closed loop portion16 may define a well 28 b sized and configured to received mechanicalamplification element 20 b. The wells 28 a and 28 b are sized to allowthe respective mechanical amplification elements 20 to rest within thewell without placing tension on the sensor 20. In other words, the wells28 a and 28 b provide a neutral position for the mechanicalamplification elements 20 to rest and not measure flow before they areslid into position over the target blood vessel and measure blood flow.

Referring back now to FIG. 1, affixed to the frame 12 is a circuitboard, for example, a printed circuit board 30 (PCB) which is sized andshape commensurate with that of the frame 12. The PCB 30 may include theprocessing circuitry having one or more processor configured to measureand monitor a change in resistance of the sensor 18 and correlate thatchange in resistance to a measure of flow. In an exemplaryconfiguration, the frame 12 is placed on top of the PCB 30 and isadhered to the PCB with glue. The PCB 30 may further include a pluralityof conductors 32 (shown in FIG. 4) coupled to respective segments of thesensor 18. For example, a first of the plurality of conductors 32 a maybe coupled to the entirety of the sensor 18 extending through the frame12. A second of the plurality of conductors 32 b may be coupled to aportion of the sensor 18 within the first substantially closed loopportion 14 and a third of the plurality of conductors 32 c may becoupled to a portion of the second 18 within the second substantiallyclosed loop portion 16. In such a configuration, sensor 18 measurementscan be isolated within each closed loop portion 14, 16 of the frame 12.The PCB 30 may further be adhered to an adhesive patch 34 sized andconfigured to be releasably adhered to skin of the mammal. In anexemplary configuration, a clinician adheres the patch 34 around thewrist of the mammal which further attaches the PCB 30 and the frame 12around the wrist of the mammal. Further coupled to the PCB 30 is aconnector 36 which extends away from the PCB 30 and is coupled to acontroller 38 (shown in FIGS. 5 and 6). In an exemplary configuration,the controller 38 is sized and configured to be placed on a portion ofthe mammal's body, for example, on the opposite side of the wrist fromthe frame 12, however the controller 38 may be positioned anywhere onthe device 10. The controller 38 may further include a display 40 havingone or more flow indicators. In one configuration, the controller 38 mayinclude red, yellow, and green LED indicators lights which indicate alevel of flow through the measured artery. For example, an occludedradial artery may trigger a red indicator light on the controller 38. Inother configurations, the controller 38 may include a display thatdisplays the actual flow measurements and/or includes an audio alert ifthe blood vessel being measured is occluded. In still otherconfigurations, the controller 38 may include a wireless transmitter(not shown) to communicate with hospital monitors, which further displayflow measurements.

It will be appreciated by persons skilled in the art that the presentinvention is not limited to what has been particularly shown anddescribed herein above. In addition, unless mention was made above tothe contrary, it should be noted that all of the accompanying drawingsare not to scale. A variety of modifications and variations are possiblein light of the above teachings without departing from the scope andspirit of the invention, which is limited only by the following claims.

What is claimed is:
 1. A medical device for measuring blood flow througha blood vessel of a mammal, comprising: a conductive elastomer having avariable resistance; a frame substantially surrounding at least aportion of the conductive elastomer, the frame including a first atleast substantially closed loop portion adjacent a second at leastsubstantially closed loop portion; and a first mechanical amplificationelement slidably coupled to the conductive elastomer and disposed withinthe first at least substantially closed loop portion; a secondmechanical amplification element slidably engaged to the conductiveelastomer and disposed within the second at least substantially closedloop portion; and the first and second mechanical amplification elementbeings configured to slide within their respective one of the first atleast substantially closed loop portion and the second at leastsubstantially closed loop portion and to contact skin of the mammal overthe blood vessel when the frame is positioned over the blood vessel, thefirst and second mechanical amplification elements being configured tobe displaced when the respective blood vessel pulsates and changes theresistance of the elastomer.
 2. The device of claim 1, wherein each ofthe first and second mechanical amplification elements defines anatraumatic skin contact surface.
 3. The device of claim 2, wherein eachof the first and second mechanical amplification elements defines anaperture opposite the atraumatic skin contact surface, and wherein theconductive elastomer is slidably received within the aperture.
 4. Thedevice of claim 1, wherein the frame is configured to flex around aportion of at least one from the group consisting of a wrist and anankle of the mammal.
 5. The device of claim 4, wherein the frame iscomposed of a flexible plastic.
 6. The device of claim 1, furtherincluding and adhesive patch coupled to the frame and adherable to skinof the mammal.
 7. The device of claim 6, further including a controllerin communication with and coupled to the conductive elastomer.
 8. Thedevice of claim 7, further including conductive electrical pathwaysdisposed between the patch and frame.
 9. The device of claim 1, whereineach of the first and second mechanical amplification elements includesa gripping element extending outward therefrom.
 10. A medical device formeasuring blood flow through a blood vessel of a mammal, comprising: aconductive elastomer having a variable resistance; a frame surroundingat least a portion of the conductive elastomer, the frame including afirst at least substantially closed loop portion adjacent a second atleast substantially closed loop portion; and a first mechanicalamplification element slidably coupled to the conductive elastomer anddisposed within the first at least substantially closed loop portion; asecond mechanical amplification element slidably coupled to theconductive elastomer and disposed within the second at leastsubstantially closed loop portion; the first and second mechanicalamplification element beings configured to slide within their respectiveone of the first at least substantially closed loop portion and thesecond at least substantially closed loop portion and to contact skin ofthe mammal over a respective blood vessel when the frame is positionedover the respective blood vessel, the first and second mechanicalamplification elements being configured to be displaced when therespective blood vessel pulsates and changes the resistance of the bloodvessel; an adhesive patch coupled to the frame and adherable to the skinof the mammal, the adhesive patching defining at least a substantiallyclosed loop about the wrist of the mammal; a printed circuit board (PCB)disposed between the patch and the frame; and a controller coupled tothe sensor and the PCB and configured to be disposed on at least aportion of wrist of the mammal, the controller including a displayconfigured to display blood flow measurements through the blood vessel.